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1.
Microbiol Spectr ; 9(2): e0129821, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1476403

ABSTRACT

Wide-scale assessment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies is critical to understanding population seroprevalence, correlates of protection, and the longevity of vaccine-elicited responses. Most SARS-CoV-2 studies characterize antibody responses in plasma/sera. While reliable and broadly used, these samples pose several logistical restrictions, such as requiring venipuncture for collection and a cold chain for transportation and storage. Dried blood spots (DBS) overcome these barriers as they can be self-collected by fingerstick and mailed and stored at ambient temperature. Here, we evaluate the suitability of DBS for SARS-CoV-2 antibody assays by comparing several antibody responses between paired plasma and DBS from SARS-CoV-2 convalescent and vaccinated individuals. We found that DBS not only reflected plasma antibody binding by enzyme-linked immunosorbent assay (ELISA) and epitope profiles using phage display, but also yielded SARS-CoV-2 neutralization titers that highly correlated with paired plasma. Neutralization measurement was further streamlined by adapting assays to a high-throughput 384-well format. This study supports the adoption of DBS for numerous SARS-CoV-2 binding and neutralization assays. IMPORTANCE Plasma and sera isolated from venous blood represent conventional sample types used for the evaluation of SARS-CoV-2 antibody responses after infection or vaccination. However, collection of these samples is invasive and requires trained personnel and equipment for immediate processing. Once collected, plasma and sera must be stored and shipped at cold temperatures. To define the risk of emerging SARS-CoV-2 variants and the longevity of immune responses to natural infection and vaccination, it will be necessary to measure various antibody features in populations around the world, including in resource-limited areas. A sampling method that is compatible with these settings and is suitable for a variety of SARS-CoV-2 antibody assays is therefore needed to continue to understand and curb the COVID-19 pandemic.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Dried Blood Spot Testing/methods , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Enzyme-Linked Immunosorbent Assay , Epitope Mapping/methods , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Neutralization Tests , SARS-CoV-2
2.
Microbiol Spectr ; 9(2): e0089021, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1443362

ABSTRACT

Measuring the antibody response to 2019 SARS CoV2 is critical for diagnostic purposes, for monitoring the prevalence of infection, and for gauging the efficacy of the worldwide vaccination effort for COVID-19. In this study, a microchip-based grating-coupled fluorescent plasmonic (GC-FP) assay was used to measure antibody levels that resulted from COVID-19 infection and vaccination. In addition, we measured the relative antibody binding toward antigens from the CoV2 virus variants strains B.1.1.7 (Alpha) and B.1.351 (Beta). Antibody levels against multiple antigens within the SARS CoV2 spike protein were significantly elevated for both vaccinated and infected individuals, while those against the nucleocapsid (N) protein were only elevated for infected individuals. GC-FP was effective for monitoring the IgG-based serological response to vaccination throughout the vaccination sequence and also resolved acute (within hours) increases in antibody levels. A significant decrease in antibody binding to antigens from the B.1.351 variant, but not B.1.1.7, was observed for all vaccinated subjects when measured by GC-FP compared to the 2019 SARS CoV2 antigens. These results were corroborated by competitive enzyme-linked immunosorbent assay (ELISA). Collectively, the findings suggest that GC-FP is a viable, rapid, and accurate method for measuring both overall antibody levels to SARS CoV2 and relative antibody binding to viral variants during infection or vaccination. IMPORTANCE In this work, a novel biosensor technology was used to measure antibody levels that resulted from vaccination against COVID-19 and/or from infection with the virus. Importantly, this approach enables quantification of antibody levels, which can provide information about the timing and level of immune response. Due the multiplexed nature of this approach, antibody binding to both the original 2019 SARS CoV-2 strain and variant strains can be performed simultaneously and in a short (30-min) time frame.


Subject(s)
Antibodies, Viral/blood , COVID-19 Vaccines/immunology , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Antibody Affinity/immunology , Biosensing Techniques , COVID-19/diagnosis , COVID-19/immunology , Dried Blood Spot Testing/methods , Enzyme-Linked Immunosorbent Assay , Humans , Immunoglobulin G/blood , Phosphoproteins/immunology , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification
3.
Microbiol Spectr ; 9(2): e0017821, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1434907

ABSTRACT

In the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, testing for SARS-CoV-2-specific antibodies is paramount for monitoring immune responses in postauthorization vaccination and seroepidemiological studies. However, large-scale and iterative serological testing by venipuncture in older persons can be challenging. Capillary blood sampling using a finger prick and collection on protein saver cards, i.e., dried blood spots (DBSs), has already proven to be a promising alternative. However, elderly persons have reduced cutaneous microvasculature, which may affect DBS-based antibody testing. Therefore, we aimed to evaluate the performance of DBS tests for the detection of SARS-CoV-2 antibodies among nursing homes residents. We collected paired venous blood and DBS samples on two types of protein saver cards (Whatman and EUROIMMUN) from nursing home residents, as well as from staff members as a reference population. Venous blood samples were analyzed for the presence of SARS-CoV-2 IgG antibodies using the Abbott chemiluminescent microparticle immunoassay (CMIA). DBS samples were analyzed by the EUROIMMUN enzyme-linked immunosorbent assay (ELISA) for SARS-CoV-2 IgG antibodies. We performed a statistical assessment to optimize the ELISA cutoff value for the DBS testing using Youden's J index. A total of 273 paired DBS-serum samples were analyzed, of which 129 were positive, as assessed by the reference test. The sensitivities and specificities of DBS testing ranged from 95.0% to 97.1% and from 97.1% to 98.8%, respectively, depending on the population (residents or staff members) and the DBS card type. Therefore, we found that DBS sampling is a valid alternative to venipuncture for the detection of SARS-CoV-2 antibodies among elderly subjects. IMPORTANCE Since the implementation of newly developed SARS-CoV-2 vaccines in the general population, serological tests are of increasing importance. Because DBS samples can be obtained with a finger prick and can be shipped and stored at room temperature, they are optimal for use in large-scale SARS-CoV-2 serosurveillance or postauthorization vaccination studies, even in an elderly study population.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Dried Blood Spot Testing/methods , Immunoglobulin G/blood , SARS-CoV-2/immunology , COVID-19/immunology , COVID-19 Vaccines/immunology , Enzyme-Linked Immunosorbent Assay , Humans , Nursing Homes , Phlebotomy/methods , Sensitivity and Specificity , Specimen Handling
4.
Sci Rep ; 11(1): 15321, 2021 07 28.
Article in English | MEDLINE | ID: covidwho-1331394

ABSTRACT

The spike protein of SARS-CoV-2 engages the human angiotensin-converting enzyme 2 (ACE2) receptor to enter host cells, and neutralizing antibodies are effective at blocking this interaction to prevent infection. Widespread application of this important marker of protective immunity is limited by logistical and technical challenges associated with live virus methods and venous blood collection. To address this gap, we validated an immunoassay-based method for quantifying neutralization of the spike-ACE2 interaction in a single drop of capillary whole blood, collected on filter paper as a dried blood spot (DBS) sample. Samples are eluted overnight and incubated in the presence of spike antigen and ACE2 in a 96-well solid phase plate. Competitive immunoassay with electrochemiluminescent label is used to quantify neutralizing activity. The following measures of assay performance were evaluated: dilution series of confirmed positive and negative samples, agreement with results from matched DBS-serum samples, analysis of results from DBS samples with known COVID-19 status, and precision (intra-assay percent coefficient of variation; %CV) and reliability (inter-assay; %CV). Dilution series produced the expected pattern of dose-response. Agreement between results from serum and DBS samples was high, with concordance correlation = 0.991. Analysis of three control samples across the measurement range indicated acceptable levels of precision and reliability. Median % surrogate neutralization was 46.9 for PCR confirmed convalescent COVID-19 samples and 0.1 for negative samples. Large-scale testing is important for quantifying neutralizing antibodies that can provide protection against COVID-19 in order to estimate the level of immunity in the general population. DBS provides a minimally-invasive, low cost alternative to venous blood collection, and this scalable immunoassay-based method for quantifying inhibition of the spike-ACE2 interaction can be used as a surrogate for virus-based assays to expand testing across a wide range of settings and populations.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/immunology , Dried Blood Spot Testing/methods , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/immunology , Antibodies, Blocking , Antibodies, Viral/immunology , COVID-19/blood , Humans , Immunoassay/methods , Neutralization Tests/methods , Reproducibility of Results , Serologic Tests
5.
EBioMedicine ; 70: 103502, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1330765

ABSTRACT

BACKGROUND: Since 2020 SARS-CoV-2 spreads pandemically, infecting more than 119 million people, causing >2·6 million fatalities. Symptoms of SARS-CoV-2 infection vary greatly, ranging from asymptomatic to fatal. Different populations react differently to the disease, making it very hard to track the spread of the infection in a population. Measuring specific anti-SARS-CoV-2 antibodies is an important tool to assess the spread of the infection or successful vaccinations. To achieve sufficient sample numbers, alternatives to venous blood sampling are needed not requiring medical personnel or cold-chains. Dried-blood-spots (DBS) on filter-cards have been used for different studies, but not routinely for serology. METHODS: We developed a semi-automated protocol using self-sampled DBS for SARS-CoV-2 serology. It was validated in a cohort of matched DBS and venous-blood samples (n = 1710). Feasibility is demonstrated with two large serosurveys with 10247 company employees and a population cohort of 4465 participants. FINDINGS: Sensitivity and specificity reached 99·20% and 98·65%, respectively. Providing written instructions and video tutorials, 99·87% (4465/4471) of the unsupervised home sampling DBS cards could be analysed. INTERPRETATION: DBS-sampling is a valid and highly reliable tool for large scale serosurveys. We demonstrate feasibility and accuracy with a large validation cohort including unsupervised home sampling. This protocol might be of big importance for surveillance in resource-limited settings, providing low-cost highly accurate serology data. FUNDING: Provided by Bavarian State Ministry of Science and the Arts, LMU University-Hospital; Helmholtz-Centre-Munich, German Ministry for Education and Research (project01KI20271); University of Bonn; University of Bielefeld; the Medical Biodefense Research Program of Bundeswehr-Medical-Service; Euroimmun, RocheDiagnostics provided discounted kits and machines.


Subject(s)
Antibodies, Viral/immunology , Biological Assay/methods , COVID-19 Serological Testing/methods , COVID-19/blood , COVID-19/immunology , Dried Blood Spot Testing/methods , SARS-CoV-2/immunology , Asymptomatic Infections , Cohort Studies , Humans , Longitudinal Studies , Sensitivity and Specificity , Specimen Handling/methods , Vaccination/methods
6.
Adv Sci (Weinh) ; 8(18): e2100323, 2021 09.
Article in English | MEDLINE | ID: covidwho-1316190

ABSTRACT

Blood cell analysis is a major pillar of biomedical research and healthcare. These analyses are performed in central laboratories. Rapid shipment from collection site to the central laboratories is currently needed because cells and biomarkers degrade rapidly. The dried blood spot from a fingerstick allows the preservation of cellular molecules for months but entire cells are never recovered. Here leucocyte elution is optimized from dried blood spots. Flow cytometry and mRNA expression profiling are used to analyze the recovered cells. 50-70% of the leucocytes that are dried on a polyester solid support via elution after shaking the support with buffer are recovered. While red blood cells lyse upon drying, it is found that the majority of leucocytes are preserved. Leucocytes have an altered structure that is improved by adding fixative in the elution buffer. Leucocytes are permeabilized, allowing an easy staining of all cellular compartments. Common immunophenotyping and mRNAs are preserved. The ability of a new biomarker (CD169) to discriminate between patients with and without Severe Acute Respiratory Syndrome induced by Coronavirus 2 (SARS-CoV-2) infections is also preserved. Leucocytes from blood can be dried, shipped, and/or stored for at least 1 month, then recovered for a wide variety of analyses, potentially facilitating biomedical applications worldwide.


Subject(s)
Communicable Diseases/diagnosis , Diagnostic Tests, Routine/methods , Dried Blood Spot Testing/methods , Hematology/methods , Immunophenotyping/methods , Antibodies, Viral/blood , Biomarkers/blood , Blood Specimen Collection/methods , COVID-19/diagnosis , Cell Separation/methods , Communicable Diseases/virology , Erythrocytes/virology , Flow Cytometry/methods , Humans , Leukocytes/virology , RNA, Messenger/blood , SARS-CoV-2/genetics
7.
Bioanalysis ; 13(15): 1183-1193, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1266825

ABSTRACT

Aim: Serological assays for the detection of anti-SARS coronavirus-2 (SARS-CoV-2) antibodies are essential to the response to the global pandemic. A ligand binding-based serological assay was validated for the semiquantitative detection of IgG, IgM, IgA and neutralizing antibodies (nAb) against SARS-CoV-2 in serum. Results: The assay demonstrated high levels of diagnostic specificity and sensitivity (85-99% for all analytes). Serum IgG, IgM, IgA and nAb correlated positively (R2 = 0.937, R2 = 0.839, R2 = 0.939 and R2 = 0.501, p < 0.001, respectively) with those measured in dried blood spot samples collected using the hemaPEN® microsampling device (Trajan Scientific and Medical, Victoria, Australia). In vitro SARS-CoV-2 pseudotype neutralization correlated positively with the solid phase nAb signals in convalescent donors (R2 = 0.458, p < 0.05). Conclusion: The assay is applicable in efficacy studies, infection monitoring and postmarketing surveillance following vaccine rollout.


Subject(s)
COVID-19/blood , Dried Blood Spot Testing/methods , High-Throughput Screening Assays/methods , SARS-CoV-2/pathogenicity , Biological Assay , Healthy Volunteers , Humans , Reproducibility of Results
8.
J Clin Virol ; 136: 104739, 2021 03.
Article in English | MEDLINE | ID: covidwho-1207042

ABSTRACT

Dried blood spot samples (DBS) provide an alternative sample type to venous blood samples for antibody testing. DBS are used by NHS for diagnosing Hepatitis C and by Public Health England for large scale HIV and Hepatitis C serosurveillance; the applicability of DBS based approaches for SARS-CoV-2 antibody detection is uncertain. The study aimed to compare antibody detection in DBS eluates using the Roche Elecsys ® immunoassay with antibody detection in paired plasma samples, using the same assay. The study was in one Police and one Fire & Rescue facility in England; it comprised of 195 participants within a larger sample COVID-19 serodiagnostics study of keyworkers, EDSAB-HOME. Outcome measures were sensitivity and specificity of DBS (the index test) relative to plasma (the reference test), at an experimental cut-off; quality of DBS sample collected; estimates of relative sensitivity of DBS vs. plasma immunoassay in a larger population. 18/195 (9.2%) participants tested positive using plasma samples. DBS sample quality varied markedly by phlebotomist, and low sample volume significantly reduced immunoassay signals. Using an experimental cut-off, sensitivity and specificity of DBS were 89.0% (95% CI 67.2, 96.9%) and 100.0% (95% CI 97.9, 100%) respectively compared with using plasma. The limit of detection for DBS is about 30 times higher than for plasma. DBS use for SARS-CoV-2 serology, though feasible, is insensitive relative to immunoassays on plasma. Sample quality impacts on assay performance. Alternatives, including the collection of capillary blood samples, should be considered for screening programs.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Dried Blood Spot Testing/methods , SARS-CoV-2/immunology , Adolescent , Adult , England , Epidemiological Monitoring , Female , Humans , Immunoassay , Limit of Detection , Male , Middle Aged , Young Adult
9.
Sci Rep ; 11(1): 7754, 2021 04 08.
Article in English | MEDLINE | ID: covidwho-1174700

ABSTRACT

Serological testing is emerging as a powerful tool to progress our understanding of COVID-19 exposure, transmission and immune response. Large-scale testing is limited by the need for in-person blood collection by staff trained in venepuncture, and the limited sensitivity of lateral flow tests. Capillary blood self-sampling and postage to laboratories for analysis could provide a reliable alternative. Two-hundred and nine matched venous and capillary blood samples were obtained from thirty nine participants and analysed using a COVID-19 IgG ELISA to detect antibodies against SARS-CoV-2. Thirty eight out of thirty nine participants were able to self-collect an adequate sample of capillary blood (≥ 50 µl). Using plasma from venous blood collected in lithium heparin as the reference standard, matched capillary blood samples, collected in lithium heparin-treated tubes and on filter paper as dried blood spots, achieved a Cohen's kappa coefficient of > 0.88 (near-perfect agreement, 95% CI 0.738-1.000). Storage of capillary blood at room temperature for up to 7 days post sampling did not affect concordance. Our results indicate that capillary blood self-sampling is a reliable and feasible alternative to venepuncture for serological assessment in COVID-19.


Subject(s)
Blood Specimen Collection/methods , COVID-19 Serological Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , Adult , COVID-19/blood , Dried Blood Spot Testing/methods , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Male , Middle Aged , Young Adult
10.
Bioanalysis ; 13(8): 621-629, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1173023

ABSTRACT

Volumetric absorptive microsampling (VAMS) is increasingly utilized for both nonclinical and clinical pharmacokinetic studies. Currently, VAMS is employed as the sampling method for the detection of antibodies for coronavirus disease 2019. Biotherapeutics whole blood stability on VAMS presents as a critical concern for the health and pharmaceutical industries. In this follow-up to our previous publication, we evaluated daclizumab and trastuzumab whole blood sample stability on VAMS. The drug recovery data we observed at room temperature for short term and -80°C for long term was very encouraging. The knowledge could help us better understand and plan important investigation timelines, especially pandemic situations where human whole blood samples from a large population are collected and in urgent need of data analysis.


Subject(s)
Antibodies, Monoclonal/blood , Antibodies, Monoclonal/pharmacokinetics , Dried Blood Spot Testing/methods , Animals , Blood Specimen Collection/methods , Daclizumab/blood , Daclizumab/pharmacokinetics , Drug Storage , Light , Rats , Tandem Mass Spectrometry , Temperature , Trastuzumab/blood , Trastuzumab/pharmacokinetics
11.
JCI Insight ; 6(9)2021 05 10.
Article in English | MEDLINE | ID: covidwho-1147004

ABSTRACT

BACKGROUNDEstimates of seroprevalence to SARS-CoV-2 vary widely and may influence vaccination response. We ascertained IgG levels across a single US metropolitan site, Chicago, from June 2020 through December 2020.METHODSParticipants (n = 7935) were recruited through electronic advertising and received materials for a self-sampled dried-blood spot assay through the mail or a minimal contact in-person method. IgG against the receptor-binding domain of SARS-CoV-2 was measured using an established highly sensitive and highly specific assay.RESULTSOverall seroprevalence was 17.9%, with no significant difference between method of contact. Only 2.5% of participants reported having had a diagnosis of COVID-19 based on virus detection, consistent with a 7-fold greater exposure to SARS-CoV-2 measured by serology than that detected by viral testing. The range of IgG level observed in seropositive participants from this community survey overlapped with the range of IgG levels associated with COVID-19 cases having a documented positive PCR test. From a subset of those who participated in repeat testing, half of seropositive individuals retained detectable antibodies for 3 to 4 months.CONCLUSIONQuantitative IgG measurements with a highly specific and sensitive assay indicated more widespread exposure to SARS-CoV-2 than observed by viral testing. The range of IgG concentrations produced from these asymptomatic exposures was similar to IgG levels occurring after documented nonhospitalized COVID-19, which were considerably lower than those produced from hospitalized COVID-19 cases. The differing ranges of IgG response, coupled with the rate of decay of antibodies, may influence response to subsequent viral exposure and vaccine.FundingNational Science Foundation grant 2035114, NIH grant 3UL1TR001422-06S4, NIH National Center for Advancing Translational Sciences grants UL1 TR001422 and UL1 TR002389, Dixon Family Foundation, Northwestern University Cancer Center (NIH grant P30 CA060553), and Walder Foundation's Chicago Coronavirus Assessment Network.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/epidemiology , Pandemics , SARS-CoV-2/immunology , Adolescent , Adult , Antibodies, Viral/blood , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing/statistics & numerical data , Chicago/epidemiology , Cohort Studies , Dried Blood Spot Testing/methods , Dried Blood Spot Testing/statistics & numerical data , Female , Humans , Immunoglobulin G/blood , Male , Middle Aged , Sensitivity and Specificity , Seroepidemiologic Studies , Young Adult
12.
J Immunol Methods ; 492: 112996, 2021 05.
Article in English | MEDLINE | ID: covidwho-1078017

ABSTRACT

Dried blood spots (DBS) are routinely used in screening newborns for treatable disorders. Immunoglobulin extraction from DBS, serum or other biological fluids loaded on filter paper cards could represent a valuable method of specimen preservation in monitoring immune response against pathogens as well as vaccination efficiency. In this study using different sources including serum, and monoclonal antibodies we established parameters for antibody extraction from the filter cards to assess antibody reactivity against Helicobacter pylori, measles virus (MV) and the novel coronavirus SARS-CoV-2 antigens. We demonstrated that DBS and dried undiluted serum result in completely preserved antibody activity for immunoassays, including in virus neutralization assays against MV. Extraction efficiency was determined by IgG concentration measurements. The plaque-reduction neutralization titer 50% of dried human serum spots remained stable after more than 10-day storage - 1:359 vs. 1:345 for the corresponding frozen sample. DBSs could be used to monitor immune response to bacterial and viral antigens following natural exposure or immunization. Mice immunized with recombinant spike protein receptor-binding domain of SARS-CoV-2 developed a strong antibody response by day 14 and reached titers above 1:64,000 on day 21 following the secondary boost immunization as measured on DBS samples in antigen-mediated ELISA. Variability in IgG concentration of eluted DBS could be influenced by factors involved in sample application, extraction process and sample characteristics. Adjustment of antibody specific activity to the eluted IgG concentration can increase accuracy of the result interpretation, including in SARS-CoV-2 serological diagnostics.


Subject(s)
Antibodies, Viral/isolation & purification , COVID-19/diagnosis , Dried Blood Spot Testing , Helicobacter Infections/diagnosis , Helicobacter pylori/physiology , Immunoassay/methods , Measles virus/physiology , Measles/diagnosis , Monitoring, Immunologic/methods , SARS-CoV-2/physiology , Animals , Antibodies, Monoclonal , Antibody Formation , Dried Blood Spot Testing/methods , Female , Humans , Immunity, Humoral , Mice , Mice, Inbred BALB C , Serologic Tests , Spike Glycoprotein, Coronavirus/immunology , Vaccination
13.
Diabetes Metab Syndr ; 15(1): 433-437, 2021.
Article in English | MEDLINE | ID: covidwho-1071268

ABSTRACT

BACKGROUND AND AIMS: The COVID-19 pandemic has led to a rapid growth in the use of telemedicine for delivery of ambulatory diabetes care. This study evaluated the feasibility of remote HbA1c monitoring via dried blood spot (DBS) testing to support assessment of glycemic control for telemedicine visits and examined clinical and demographic characteristics associated with patient completion of DBS testing. METHODS: Providers could place orders for DBS HbA1c 3 weeks prior to telemedicine visits. Feasibility was assessed by examining DBS completion rates, time to completion, and availability of DBS results prior to telemedicine visits. Chi-square tests and Mann Whitney tests were used to assess whether completion rates were associated with participant characteristics. RESULTS: Of 303 DBS orders placed for telemedicine visits in June 2020, 162 patients completed the DBS test for a completion rate of (53.4%). Average time from collection at home to result being reported was 6.9 (3.8) days. The DBS result was available in 67.6% of patients who completed successful DBS, before the telemedicine clinic visit. HbA1c was lower in the DBS completion group as compared to the non-completion group (8.2% vs. 8.9%, p = 0.01). No other clinical or demographic characteristics were significantly different between the two groups. CONCLUSION: Remote HbA1c monitoring via DBS is feasible and offers an avenue to support assessment of glycemic control for patients seen via telemedicine. Future work should focus on improving clinic and laboratory processes to support remote DBS collection.


Subject(s)
COVID-19/epidemiology , Diabetes Mellitus/blood , Diabetes Mellitus/epidemiology , Dried Blood Spot Testing/methods , Glycated Hemoglobin A/metabolism , Telemedicine/methods , Adaptation, Psychological , Adolescent , COVID-19/prevention & control , Child , Diabetes Mellitus/diagnosis , Dried Blood Spot Testing/trends , Feasibility Studies , Female , Humans , Male , Telemedicine/trends
14.
Am J Hum Biol ; 32(5): e23394, 2020 09.
Article in English | MEDLINE | ID: covidwho-1005715

ABSTRACT

OBJECTIVES: Investigating factors that contribute to bone loss and accretion across populations in remote settings is challenging, particularly where diagnostic tools are scarce. To mitigate this challenge, we describe validation of a commercial ELISA assay to measure osteocalcin, a biomarker of bone formation, from dried blood spots (DBS). METHODS: We validated the Osteocalcin Human SimpleStep ELISA kit from Abcam (ab1951214) using 158 matched plasma and DBS samples. Passing-Bablok regression analysis assessed the relationships between plasma and DBS osteocalcin concentrations. Dilutional linearity and spike and recovery experiments determined if the DBS matrix interfered with osteocalcin measurement, and intra- and inter-assay coefficients of variation (CVs) were calculated. Limit of detection, analyte stability, and specific forms of osteocalcin measured by the kit were also investigated. RESULTS: Mean plasma osteocalcin value was 218.2 ng/mL (range 64.6-618.1 ng/mL). Linear relationships existed between plasma and DBS concentrations of osteocalcin, with no apparent bias in plasma vs DBS concentrations. There was no apparent interference of the DBS matrix with measurement of osteocalcin in DBS. Intra-assay CV for DBS was ~8%, while average inter-assay CV was 14.8%. Limit of detection was 0.34 ng/mL. Osteocalcin concentrations were stable in DBS stored at -28°C and room temperature, but not those stored at 37°C. This ELISA kit detects total osteocalcin. CONCLUSIONS: Osteocalcin, a bone formation biomarker, can be measured from DBS. Combined with a previously validated DBS assay for TRACP-5b, a bone resorption biomarker, these assays have the potential to help researchers disentangle the many factors contributing to bone strength.


Subject(s)
Dried Blood Spot Testing/methods , Enzyme-Linked Immunosorbent Assay/methods , Osteocalcin/blood , Osteogenesis/physiology , Adult , Aged , Biomarkers/blood , Dried Blood Spot Testing/instrumentation , Enzyme-Linked Immunosorbent Assay/instrumentation , Female , Humans , Male , Middle Aged , Oregon , Reproducibility of Results , Young Adult
15.
Drug Test Anal ; 13(1): 223-226, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-910190

ABSTRACT

At the beginning of 2020, an outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reached pandemic dimensions. Throughout the event, diagnostic tests function as an essential tool for understanding, mitigating, and implement strategies to curb and reduce infections. Here, we present a novel method for the fully automated dried blood spot (DBS) sample handling and extraction for serological testing of human IgG antibodies against SARS-CoV-2 using a commercial enzyme-linked immunosorbent assay (ELISA) testing kit. This proof-of-principle pilot study successfully demonstrates the recovery of antibodies in their intact form from DBS using automated, direct sample elution within 100 µl of extraction buffer. The use of minimally invasive DBS sampling provides an alternative to existing analytical procedures such as sampling by venipuncture or nasal swabs. Due to the ease of DBS collection, no third party need be involved, making at-home sampling possible (e.g., during quarantine).


Subject(s)
Antibodies, Viral/analysis , COVID-19 Testing/methods , COVID-19/diagnosis , COVID-19/immunology , Dried Blood Spot Testing/methods , SARS-CoV-2/immunology , Automation , Dried Blood Spot Testing/instrumentation , Enzyme-Linked Immunosorbent Assay , Humans , Immunoglobulin G/analysis , Pandemics , Pilot Projects , Specimen Handling
16.
Emerg Infect Dis ; 26(12): 2970-2973, 2020 12.
Article in English | MEDLINE | ID: covidwho-792953

ABSTRACT

Dried blood spot (DBS) samples can be used for the detection of severe acute respiratory syndrome coronavirus 2 spike antibodies. DBS sampling is comparable to matched serum samples with a relative 98.1% sensitivity and 100% specificity. Thus, DBS sampling offers an alternative for population-wide serologic testing in the coronavirus pandemic.


Subject(s)
COVID-19/diagnosis , Dried Blood Spot Testing/methods , Antibodies, Viral/immunology , COVID-19 Serological Testing/methods , Case-Control Studies , Dried Blood Spot Testing/economics , Humans , Predictive Value of Tests , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/isolation & purification
17.
PLoS One ; 15(8): e0236775, 2020.
Article in English | MEDLINE | ID: covidwho-768798

ABSTRACT

BACKGROUND: Options to increase the ease of testing for SARS-CoV-2 infection and immune response are needed. Self-collection of diagnostic specimens at home offers an avenue to allow people to test for SARS-CoV-2 infection or immune response without traveling to a clinic or laboratory. Before this study, survey respondents indicated willingness to self-collect specimens for COVID-related tests, but hypothetical willingness can differ from post-collection acceptability after participants collect specimens. METHODS: 153 US adults were enrolled in a study of the willingness and feasibility of patients to self-collect three diagnostic specimens (saliva, oropharyngeal swab (OPS) and dried blood spot (DBS) card) while observed by a clinician through a telehealth session. After the specimens were collected, 148 participants participated in a survey about the acceptability of the collection, packing and shipping process, and their confidence in the samples collected for COVID-related laboratory testing. RESULTS: A large majority of participants (>84%) reported that collecting, packing and shipping of saliva, OPS, and DBS specimens were acceptable. Nearly nine in 10 (87%) reported being confident or very confident that the specimens they collected were sufficient for laboratory analysis.There were no differences in acceptability for any specimen type, packing and shipping, or confidence in samples, by gender, age, race/ethnicity, or educational level. CONCLUSIONS: Self-collection of specimens for SARS-CoV-2 testing, and preparing and shipping specimens for analysis, were acceptable in a diverse group of US adults. Further refinement of materials and instructions to support self-collection of saliva, OPS and DBS specimens for COVID-related testing is needed.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Oropharynx/virology , Patient Compliance , Pneumonia, Viral/diagnosis , Saliva/virology , Specimen Handling/methods , Adult , Betacoronavirus/genetics , COVID-19 , Coronavirus Infections/virology , Dried Blood Spot Testing/methods , Educational Status , Female , Humans , Male , Middle Aged , Pandemics , Patient Compliance/ethnology , Pneumonia, Viral/virology , SARS-CoV-2 , Self Care , Surveys and Questionnaires , Telemedicine
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